11.2 Producing Visible Light
page 431
Give five examples of natural sources of light:
What is natural vs. artificial light?
Type
How it works
Bioluminescence
Incandescent light
How is incandescent light produced?
How do incandescent lightbulbs work?
Why aren’t incandescent lightbulbs used anymore?
Fluorescent light
How is fluorescent light produced?
How does a fluorescent lightbulb work?
How do fluorescent bulbs compare to incandescent bulbs in terms of
efficiency?
Phosphorescent light
How does phosphorescence differ from fluorescence?
If a glow--in-the-dark object has lost its glow, how can you make it
glow again?
Examples
Type
Chemiluminescence
How it works
Examples
What is chemiluminescence?
How is chemiluminescence involved in detecting blood traces?
How does a glowstick work?
Electroluminescence
What is an LED?
How are LED lights different than fluorescent lights?
REVIEW:
1. Why would replacing heat lamps with fluorescent bulbs to keep baby chicks warm be less effective?
2. If a black light causes other things to glow, what category (from the table) would it fit into?
3. How are chemiluminescence and bioluminescence related?
4. Why would chemiluminescence sometimes be referred to as “cool light”?
11.2 Producing Visible Light
page 431
Give five examples of natural sources of light:
lightning bug, sun, fire, lightning, angler fish, glow worms, stars, jellyfish
What is natural vs. artificial light?
Natural light is produced by things in nature. Artificial light is man-made.
Type
How it works
Examples
Bioluminescence
- the production of light from a chemical reaction within
an organism
- purpose: scare predators, lure prey, attract mates
- firefly, angler
fish...
Incandescent light
How is incandescent light produced?
when substances (metal) are heated and produce light
- lightbulb, candle
How do incandescent lightbulbs work?
Electricity is passed through the thin coiled wire (filament)
which glows and becomes hot
Why aren’t incandescent lightbulbs used anymore?
they produce too much heat - inefficient
Fluorescent light
How is fluorescent light produced?
- a substance absorbs UV radiation and glows
lightbulb, black
light shows (UV
light)
How does a fluorescent lightbulb work?
- the inside of the glass tube absorbs UV light created when
electricity passes through a gas
- the inside of the glass glows
How do fluorescent bulbs compare to incandescent bulbs in
terms of efficiency?
- saves energy, last longer (fluorescent)
http://www.youtube.com/watch?v=4qCDn5SjcTs
Phosphorescent light
How does phosphorescence differ from fluorescence?
substances that glow-in-the-dark without needing heat,
electricity because they have the ability to store energy and
release it slowly
If a glow-in-the-dark object has lost its glow, how can you
make it glow again?
hold it under light
glow-in-the-dark
Type
Chemiluminescence
How it works
Examples
What is chemiluminescence?
the production of light by mixing chemicals (no heat)
How is chemiluminescence involved in detecting blood traces?
How does a glowstick work?
Electroluminescence
What is an LED?
Light-emitting diode
digital watches,
Cell phones, tvs...
How are LED lights different than fluorescent lights?
save more energy, last even longer, stay cooler
REVIEW:
1. Why would replacing heat lamps with fluorescent bulbs to keep baby chicks warm be less effective?
2. If a black light causes other things to glow, what category (from the table) would it fit into?
3. How are chemiluminescence and bioluminescence related?
4. Why would chemiluminescence sometimes be referred to as “cool light”?